In the next-generation (e.g., fifth generation (5G) New Radio (NR)) wireless network, multi-connectivity (MC) including dual-connectivity (DC) is envisioned to support more capacity, data, and services. A user equipment (UE) configured with multi-connectivity may have one master node as an anchor and one or more secondary nodes. For example, a UE in multi-connectivity may be configured with one master cell group (MCG) and one or more secondary cell groups (SCGs) for data delivery. Each cell group may be formed by one or more cells. All cell groups are not necessarily the same type. For example, one can be a Long Term Evolution (LTE) or an evolved LTE (eLTE) cell group, while another one can be an NR cell group. Regarding to the core network, taking E-UTRA (Evolved Universal Terrestrial Radio Access) for example, the core network that E-UTRA connects to can be the Evolved Packet Core (EPC) or NextGen Core (NGC) or 5G Core Network (5GC). eLTE is also known as LTE connected to 5GC. In NR-NR DC case and Multi-RAT (MR)-DC (e.g., NR-NR DC, EN (E-UTRAN New Radio)-DC, or New Radio E-UTRAN (NE)-DC) case, each network node may have its own Radio Resource Control (RRC) entity, but the UE's RRC entity may follow that of the master node.
While a UE in multi-connectivity may maintain simultaneous connections with the master node and the secondary node(s), in some cases, the UE may not camp to a cell even though the cell is suitable for being the UE's secondary node.
Thus, there is a need in the art for an improved secondary node addition mechanism for multi-connectivity.